Silicon carbide (SiC) is expected as a material for next generation semiconductor devices. Compared to silicon, silicon carbide has superior physical properties such as a band gap of about 3 times, a breakdown field strength of about 10 times, and a thermal conductivity of about 3 times. By utilizing the physical properties, it is possible to realize a semiconductor device capable of operating with low loss and at high temperature.
As a structure for reducing an on-resistance of a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) using silicon carbide, there is a trench gate type MOSFET in which a gate electrode is provided in a trench. In the trench gate type MOSFET, the on-resistance is reduced by increasing the channel density per unit area. In a trench gate type MOSFET, it is expected to realize a structure for further reducing the on-resistance.